6. Salicylic acid compared to no treatment.
| Salicylic acid compared to no treatment for acne | ||||||
| Patient or population: participants with acne Settings: Skin Disease and Leishmaniasis Research Center and Isfahan University of Medical Sciences clinics (1 study); a tertiary care hospital of Eastern India (1 study); not described (1 study) Intervention: topical salicylic acid Comparison: no treatment | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo/no treatment | Topical salicylic acid | |||||
|
Participants' global self‐assessment of acne improvement
Moderate to excellent improvement (long term: treatment duration > 8 weeks) |
1000 per 1000 | 960 per 1000 (860 to 1000) | RR 0.96 (0.86 to 1.07) | 50 (1 study) | ⊕⊕⊝⊝ Lowa | Clindamycin/benzoyl peroxide was a co‐intervention given in both arms. |
|
Withdrawal for any reason (long term: treatment duration > 8 weeks) |
‐ | ‐ | RR 3.0 (0.13 to 70.30) | 138 (3 studies) | ⊕⊝⊝⊝ Verylowb | Two studies had no withdrawals. |
|
Total number of participants who experienced at least one minor adverse event (long term: treatment duration > 8 weeks) |
436 per 1000 |
1000 per 1000 (61 to 1000) |
RR 3.43 (0.14 to 82) | 78 (2 studies) | ⊕⊝⊝⊝ Verylowc | All side effects reported in the study were of mild to moderate intensity and transient. |
|
Quality of life AQOL (long term: treatment duration > 8 weeks) |
The authors reported no "significant differences" in AQOL between treatment groups (salicylic acid/clindamycin/benzoyl peroxide group versus clindamycin/benzoyl peroxide group) at baseline and the end of the study. | 50 (1 study) | ⊕⊝⊝⊝ Very lowd |
Median and 95% CI reported. | ||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). AQOL: acne quality of life; CI: confidence interval; RR: risk ratio. | ||||||
| GRADE Working Group grades of evidence High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate. | ||||||
aDowngraded by two levels to low quality evidence. One level for risk of bias: only one study included with high risk of performance bias and unclear risk of selection bias. One level for imprecision: optimal sample size not met. bDowngraded by three levels to very low quality evidence. One level for risk of bias: three studies included and all with unclear risk of allocation concealment and high risk of performance bias, two studies with unclear risk of random sequence generation. Two levels for imprecision: very wide CI and optimal sample size not met. cDowngraded by three levels to very low quality evidence. One level for risk of bias: two studies included and both with unclear risk of selection and high risk of performance bias, one with unclear risk of reporting bias. Two levels for imprecision: very wide CI and optimal sample size not met. dDowngraded by three levels to very low quality evidence. One level for risk of bias: only one study included with high risk of performance bias and unclear risk of selection bias. One level for imprecision: very small total sample size. *We choose a mean baseline risk from the studies included in meta‐analysis, calculated as number of participants in the control groups with event divided by total number of participants in control groups (study population) as assumed risk.